Titanium or steel freehub body for DT hubs?

Everything about building wheels, glueing tubs, etc.
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ergott
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by ergott

eric01 wrote:
Tue Feb 13, 2018 3:31 am
Actually, Shimano DID try to address the problem. They tried with the Dura Ace 7800 high spline freehub in aluminum. Lasted 1 generation and never trickled down to Ultegra or 105. 7900 went back to titanium low spline.

The market spoke -- didn't catch on. The low spline was too far ingrained.

There's a reason Shimano doesn't make an aluminum low spline freehub...
The market didn't speak. They dipped their toes in the water and didn't commit to the solution. They decided not to have the solution trickle down. It wasn't a lack of people buying Dura Ace at the time.

by Weenie


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ergott
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by ergott

mattr wrote:
Tue Feb 13, 2018 10:52 am
Shimano don't have a problem.
They designed a spline interface suitable for manufacture in certain grades of steel and titanium.
Yes, and the other manufacturers make perfectly acceptable solutions that are significantly lighter and less expensive to manufacture. How is that not a legitimate critique of Shimano? :noidea:

So the point of Dura Ace isn't to make things lighter without sacrificing durability if they can? I thought that's exactly what Dura Ace was about. There's no performance loss with Sram or Campagnolo cassette systems.

mattr
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by mattr

ergott wrote:
Tue Feb 13, 2018 2:38 pm
mattr wrote:
Tue Feb 13, 2018 10:52 am
Shimano don't have a problem.
They designed a spline interface suitable for manufacture in certain grades of steel and titanium.
Yes, and the other manufacturers make perfectly acceptable solutions that are significantly lighter and less expensive to manufacture. How is that not a legitimate critique of Shimano? :noidea:

So the point of Dura Ace isn't to make things lighter without sacrificing durability if they can? I thought that's exactly what Dura Ace was about. There's no performance loss with Sram or Campagnolo cassette systems.
Because they have different design guidelines to follow than Campag and SRAM. So your definition of "performance" is pretty much irrelevant. So are SRAM and Campags. Shimano have a reason (whichever it is, i can think of several) to not go to smaller bearings and deeper splines (Or an XD arrangement).
They've decided that their particular loose bearing/spline/freehub design meets all their requirements (weight, assembly, durability, serviceability, performance, whatever), so why change just to support everyone else?

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ergott
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by ergott

The Sram cassette design fits on Shimano splines so your point about larger bearings is irrelevant. They managed to have an interface that doesn't kill a lighter, more inexpensive material.

Care to share your "several" reasons?

Why change? Because there's a better solution.

mattr
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by mattr

ergott wrote:
Tue Feb 13, 2018 3:03 pm
The Sram cassette design fits on Shimano splines so your point about larger bearings is irrelevant. They managed to have an interface that doesn't kill a lighter, more inexpensive material.
You don't even know what my point is. And for what it's worth, low end SRAM cassettes with individual/riveted sprockets cut up aluminium freehubs.
ergott wrote:
Tue Feb 13, 2018 3:03 pm
Care to share your "several" reasons?
Not much point, you have already decided that the shimano solution doesn't meet your particular set of requirements. Stick with campag and SRAM .
ergott wrote:
Tue Feb 13, 2018 3:03 pm
Why change? Because there's a better solution.
Only in your opinion. In the real world, there are a handful of competing solutions, all of which have benefits (and shortcomings).

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ergott
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by ergott

mattr wrote:
Tue Feb 13, 2018 3:22 pm
Not much point, you have already decided that the shimano solution doesn't meet your particular set of requirements.
I don't know your point because you haven't made one yet.

Wow, talk about a cop out. You've proceeded to tell me I'm wrong but not why.

pdlpsher1
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by pdlpsher1

I’m now using a 11-34 cassette and the Red stops at 11-32. So I’m stuck with Shimano until Sram comes out with a 11-34. Previously I was on the Red 11-28. So Sram isn’t an option for everyone.

So would higher locking torque really solve the issue?


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ergott
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by ergott

The listed torque spec is higher than most people actually tighten their cassettes (from the ones I’ve serviced). At the correct spec you definitely reduce the amount of gouging, but it won’t be completely eliminated.

pdlpsher1
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by pdlpsher1

Thanks. I will have to get a new and bigger torque wrench or just go by feel.

One solution Shimano could adopt is to integrate the spacers into the smaller cogs. So in effect make each cog thicker in the middle and eliminate the aluminum spacers. But this would make them heavier and most costly to manufacture.


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Last edited by pdlpsher1 on Tue Feb 13, 2018 7:36 pm, edited 1 time in total.

Svetty
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by Svetty

So you get a slightly gouged freehub - so what?

It's only an issue when changing cassette and then only by making it a slightly longer process to remove the cogs. It's easy enough to lightly file down any protruding aluminium before re-fitting the cassette - and if you torque the cassette properly the gouging is reduced to a minimum.

Having said this I'm not a 1600 watt power-sprinter but the point still stands.

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by Multebear

I'm not paying 330 quid for a pair of hubs that needs filing after 1 year of use. And next thing, in northern european weather conditions, there's either rain or damp roads all winter. I clean my bike after each ride, and I prefer to remove cassette and clean that as well when needed. I don't want to accept to wrestle off the cogs before every cleaning. That's just unacceptable. If they were cheap hubs, then it would be acceptable, but not high-end hubs.
Last edited by Multebear on Tue Feb 13, 2018 10:48 pm, edited 1 time in total.

mattr
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by mattr

ergott wrote:
Tue Feb 13, 2018 3:37 pm
I don't know your point because you haven't made one yet.
Larger bearings, all things being equal, are better than smaller bearings. That's the jist of it.
So 9 x 1/4" bearings plus the cup and cone around a threaded 10mm axle gives you enough load/speed capacity to meet shimanos design criteria (which is more than likely different to campag). It also allows easy adjustability, reasonable size for service/access/tools, only two rotating elements on the axle (rather than the 4 of almost all their competitors) and because the bearing races are pretty close to both drop outs (rather than just one) supports the hub/wheel system better. Cup and cone is also arguably better suited to use here than deep groove cartridge.
It also gives you your minimum inner diameter of the freehub. Minimum outer diameter is limited by the smallest sprocket size (12t i think when they started out with uniglide. May have had a smaller one, but i never needed one, so never looked too hard!) thats now gone down to 11, as the top sprocket is no longer threaded, so doesn't need the same sort of strength/material. So that restricts your spline depth. And pretty much gives you two material choices, either steel or a moderately reasonable grade of Ti. (There are others)
Also, the other driver is that the hyperglide design is common across their entire range and has been for ~30 years, it's as close to a standard as the cycling industry has these days. So the machining costs are minimal per unit, the higher R&D/Tooling is sunk across a *massive* volume, even D-A hubs are probably selling 6 figures a year. So even the extra costs of grinding and heat treating cups and cones are again minimised. I'd not be surprised if the machines currently doing Acera bits are the same ones that they did the 7700 on :wink:

The alternative solutions use smaller cartridge bearings in the freehub. Also only support the wheel at centre and left hand drop out (needing a more complex axle design), generally aren't that serviceable or adjustable. (bearings go in the bin when they get sloppy.) You've got four rolling elements on the axle, not two so the axle needs to be far straighter and is less tolerant of misalignment. Sealing is more tricky as well as you have a rotating joint in the middle. Also the freehub bearings are moving almost all the time (in a shimano hub, under power the freewheel bearings aren't moving in relation to the races, only the large wheel bearings rotate) so they are more likely to fail early, compounded by any misalignment of the axle. You also need special tools to "service" the hub. (Bash the bearings out, new ones in) rather than cone spanners that have been round almost since jesus was a lad.

I can see almost all the differences between shimanos philosophy to everyone elses. And the main issue that the end user has (gouging) is essentially as using a more suitable material is more expensive to machine. And usually heavier.
And i can also see exactly why shimano don't see any need to change yet. There isn't actually a better solution, just ones with different downsides.

For what it's worth, changing material without reviewing and /or updating the design is a massive issue across engineering, not just cycling, especially bad when going metal to composite. But even hard metal to soft is causes issues. Look at early aluminium bike parts....... never lasted long, looked very similar to the steel ones they replaced. No design review.

I also own DT swiss, Hope, Easton, mavic and Bontrager hubs. So i'm not immune to the attraction of a shiny lightweight CNCed hub. Even if i know that it's not as thoroughly engineered as the (many) shimano hubs i have. And unlikely to last as long, given the same sort of use and care.

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ergott
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by ergott

I agree with all that. My point is that Sram has a cassette (Red) that is lighter than Dura Ace and fits on the same freehub dimensions as Shimano so no change in hubs design needed. You could have an aluminium carrier (also lighter) and same inner dimensions to clear the larger bearing bores found in Shimano specific hubs.

The Sram design has one set of teeth/splines that are significantly wider and don't gouge aluminium freehubs in the middle cogs like Shimano (and to be fair lower end Sram). The result is a lighter system maintaining Shimano's standard.

I also agree that Campagnolo cheated on their design. Deeper splines limits bearing dimensions inside the freehub. I practice I don't know just how much performance or durability is lost, but yes larger bearings are nice if you can make it work.

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ergott
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by ergott

PS for all Shimano's attention to good engineering they shat the bed with their flange placement on Dura Ace hubs (9100). There's a very significant resulting tension difference between the sides requiring I high minimum tension on the right to make for acceptable tension on the left. They essentially shifted both flanges over 1.8mm and didn't rethink left flange placement. Rims with a low max tension will have a problem.

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sungod
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by sungod

Multebear wrote:
Tue Feb 13, 2018 8:30 pm
I'm not paying 330 quid for a pair of hubs that needs filing after 1 year of use. And next thing, in northern european weather conditions, there's either rain or damp roads all winter. I clean my bike after each ride, and I prefer to remove cassette and clean that as well when needed. I don't want to accept to wrestle off the cogs before every cleaning. That's just unacceptable. If they were cheap hubs, then it would be acceptable, but not high-end hubs.
you know that shimano cassettes gouge light alloy hubs, it's not the fault of the hub, it's not the fault of the cassette, they simply aren't compatible

saying " That's just unacceptable. If they were cheap hubs, then it would be acceptable, but not high-end hubs." is blaming the hub, sorry but that's your fault for mixing components that are well known to have this incompatibility

solution 1: use a cassette that won't gouge the hub
solution 2: use a different hub

by Weenie


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